The invention relates to an apparatus for regulating the breathing pattern of a patient, comprising a sensor adapted to be attached to the body of the patient and responsive to the contractions and expansions of the chest, and means to convert the output signals of the sensor into short control impulses of which the repetition frequency is equal to the breathing frequency, and which provide a criterion for the regulation of the breathing pattern.
U.S. Pat. No. 3,802,417 (Lang) discloses an apparatus of this kind to regulate the breathing pattern of a pre-mature or newborn child. In this case the control impulses derived from the output signals of the sensor are counted for a predetermined period, for instance ten seconds. If the number of impulses within that period is below a predetermined value, an artificial respiration device is actuated to restore a regular breathing pattern. In the regulation of the breathing pattern of a small child the use of a sensor responsive to the contractions and expansions of the chest may be unsatisfactory, because control impulses may be generated by body movements that have nothing to do with breathing. It is therefore preferred in such a case to use a sensor inserted in the nose or the throat and responsive to the respiration air flow.
U.S. Pat. No. 2,934,060 (Satter) discloses a tone generator alternately producing two audible tones having a different character for the purpose of putting a person to sleep. In this case the repetition frequency of the audible tones is initially adjusted to the breathing frequency of the person. The tone generator is constructed in such manner that the repetition frequency of the tones is gradually reduced, thereby inducing a reduction of the breathing frequency whereby the person eventually goes asleep. It is of course not useful in this case to control the operation of the tone generator by means of a sensor.